1. Field of the Invention
The present invention relates to a method of fabricating a self-aligned bipolar transistor, in which silicide is formed after completion of impurity ion implantation using a gate polysilicon and sidewall as an ion implantation mask.
2. Discussion of the Related Art
FIGS. 1A to 1C are cross-sectional diagrams for explaining a method of fabricating a self-aligned bipolar transistor according to a related art.
Referring to FIG. 1A, after a device isolation layer 12 has been formed on a substrate 11 provided with a prescribed device, ion implantation is performed on a prescribed area of the substrate 11 to form a well 13.
Subsequently, photoresist is coated on the substrate 11. Exposure and development are carried out on the photoresist to form a photoresist pattern 14 for ion implantation.
Ion implantation is carried out on the substrate using the photoresist pattern 14 as an ion implantation mask to for a P+ ion implanted region 15 and an N+ ion implanted region 16 in the substrate 11.
Referring to FIG. 1B, after the photoresist pattern has been removed from the substrate 11, an oxide layer pattern 17 is formed on the substrate 11.
Subsequently, a silicidation process is carried out on the substrate to form a silicide layer 18 on the exposed portion of the substrate 11.
Referring to FIG. 1C, after the oxide layer pattern has been removed from the substrate 11, a collector 19, an emitter 20, and a base 21 are formed in the well 13 of the substrate 11.
However, the related art bipolar transistor forming method needs a patterning work according a generation rule of a mask to form the emitter, collector, and base junctions and also needs a patterning work for forming silicide selectively on the substrate by photolithography, whereby device reliability can be degraded in case of misalignment occurrence in performing the patterning work.